This invention relates to an improved plastic closure such as a cap or collar for closing or sealing containers such as vials containing a medicament which eliminates the problems associated with a malleable metal cap or collar such as aluminum. The plastic closure of this invention may be used as a cap to seal a conventional vial having an elastomeric stopper or as a collar for retaining a fluid transferset separate from or integral with the collar.
It is conventional to store medicament such as drugs in a sealed vial or other container for later use. Such medicaments may be in a dry or powdered form to increase the shelf life of the drugs and reduce inventory space. Such dry or powdered drugs are generally stored in a sealed vial and reconstituted in liquid form for administration to a patient by adding a diluent or solvent. Alternatively, the drug may be in liquid or even gaseous form. A conventional vial for storing medicament generally includes an open end, a radial rim portion surrounding the open end and a reduced diameter neck portion adjacent the rim portion. The vial is conventionally sealed with an elastomeric stopper which generally includes a tubular portion inserted into the neck of the vial and a planar rim portion which overlies the vial rim. The stopper is normally secured to the vial with a thin malleable metal cap, such as aluminum. The aluminum cap includes a tubular portion which surrounds the rim portions of the stopper and vial, an inwardly projecting annular portion which overlies the rim portion of the stopper and a distal end portion which is crimped or deformed radially into the vial neck beneath the vial rim portion. Because aluminum is malleable, the collar accommodates the buildup of tolerances of the dimensions of the stopper and vial rim. The dimensions and tolerances of standard vials and stoppers are set by the International Standards Organization (ISO).
The radial portion of the aluminum cap which overlies the stopper rim portion may be closed, in which case the aluminum cap is removed by xe2x80x9cpeelingxe2x80x9d the aluminum cap from the vial. A pre-slit tab located in the middle area is provided which overlies the vial rim, permitting the cap to be torn from the top and peeled from the vial prior to use. This closed embodiment of an aluminum cap has several disadvantages. First, the tearing of the metal cap creates sharp edges which may cut or damage sterile gloves and cut the person administering the drug, thereby exposing both the healthcare worker and the patient to disease and contamination of the drug. Second, the tearing of the aluminum cap generates metal particles which may also contaminate the drug. The dangers associated with the tearing of an aluminum cap has been solved in part by adding a xe2x80x9cflip-offxe2x80x9d plastic cap. In one such embodiment, the aluminum collar includes a central opening and a shallow plastic cup-shaped cap is received over the aluminum collar having a central projecting riveting portion which is received and secured in the central opening of the aluminum collar. The plastic cap is then removed by forcing the flip-off cap away from the aluminum collar, which tears an annular serrated portion surrounding the central opening and exposes an opening in the collar for receipt of a hypodermic needle or the like. This embodiment reduces but does not eliminate the possibility of tearing the sterile gloves of the healthcare worker. More importantly, however, aluminum dust is still created which may contaminate the medicament. It is also important to note that metallic dust is also created simply by forming and affixing the aluminum collar to the vial because aluminum dust is created in forming the aluminum collar, crimping of the collar and removal of the flip-off plastic cap.
Aluminum collars have also been used to secure a fluid transferset on medicament vials. Transfersets may be utilized, for example, to transfer fluid from a syringe to a vial, such as to reconstitute a dry or powdered drug in a vial by adding a diluent or solvent. The reconstituted drug may then be withdrawn from the vial by the syringe. The inner surface of the transferset may be part of the drug fluid path and the aluminum collar or ring may bring aluminum particles in the sterile room where the drug is added to the vial or into the drug fluid path contaminating the drug. There have been attempts to reduce this problem by applying a coating to the aluminum cap or collar. Finally, the prior art also includes snap-on cup-shaped plastic caps or collars having a radially inwardly projecting end portion which is snapped over the rim portion of the vial. Snap-on plastic collars, however, do not assure adequate sealing of the vial or fully accommodate the tolerances of standard vials and stoppers as required.
The need therefore remains for a closure for vials and other medical containers which may be utilized with conventional containers, such as medicament vials or cartridges, which assures sealing of the container and which achieves a good level of cleanliness, without metal particles or dust which may contaminate the medicament, the transferset or the clean room and which does not expose the healthcare worker to sharp metal edges. The plastic closure of this invention solves these problems and permits the use of the plastic closure of this invention for attaching and sealing containers and fluid transfersets as described below.
As set forth above, the plastic closure for sealing a vial or other medical container of this invention eliminates the problems associated with a malleable metal or aluminum cap or collar, but which accommodates the buildup of tolerances of the rim portion of the container and the elastomeric stopper, when used. The plastic closure of this invention is relatively inexpensive to manufacture and use. The plastic closure of this invention may be utilized as a cap to seal a conventional medicament vial, as a collar in combination with a flip-off cap or as a collar used to secure and seal a transferset on a vial for transferring fluid between a vial or other container and a second container. As used herein, the term closure is generic to either a cap or collar.
As stated, the plastic closure for sealing a container of this invention may be utilized with a conventional vial having an open end and a reduced diameter neck portion adjacent the open end. The plastic closure of this invention includes a generally tubular portion and a portion which is deformed radially or crimped into the reduced diameter portion of the container to retain the closure on the container and as a cap to seal the open end of the container. The plastic closure of this invention may also be used as a cap or collar with a conventional vial and elastomeric stopper In the preferred embodiment, the plastic closure of this invention is formed of a polymer which is sufficiently malleable to permit radial deformation, yet sufficiently rigid to retain its shape following deformation and sufficiently resistant to creep to maintain the seal between the plastic cap and the container following radial deformation.
The preferred embodiment of the plastic closure of this invention is formed of a polymer alloy or melt blend which includes a relatively tough soft malleable copolymer and a relatively rigid polymer. In the most preferred embodiment of the plastic closure of this invention, the composite polymer is a polymer alloy of a relatively soft malleable co-polymer and a relatively rigid polymer. The preferred relatively rigid polymer is a polyamid or a polycarbonate and the preferred relatively soft co-polymer may be selected from polyesters or polyolefins. The resultant polymer alloy or composite preferably has an elongation at yield between 5% and 10% and an elongation at break greater than 100% with a flectural modulus of greater than 1900 MPa.
Where the container includes a radial rim portion adjacent the open end, the plastic closure of this invention includes a generally cylindrical tubular portion preferably having an internal diameter generally equal to or slightly greater than the external diameter of the rim portion of the container adapted to be received over the rim portion of the container having a free distal end adapted to be deformed radially inwardly or crimped beneath the rim portion of the container and sealed relation. The plastic cap or collar of this invention may also include a radially inwardly projecting proximate portion which overlies the rim portion of the container and/or the stopper. This radial portion may be closed or more preferably includes a central opening which may be closed with a flip-off or peel-off type plastic closure or seal. In the preferred embodiment, the peel-off seal includes a looped end portion which is welded or glued to the tubular portion surrounding the transferset providing indication of tampering and a free end which may be gripped to remove the seal.
Where the plastic collar of this invention is utilized to secure a transferset for transferring fluid from the container to a second container, the preferred embodiment of the collar includes a second tubular portion which at least partially surrounds the internal components of the transferset. In one preferred embodiment, the second tubular portion completely surrounds the internal components of the transferset, which may have a closed end integral with the second tubular portion or closed with a sealing member. In the most preferred embodiment, the collar portion is integral with the tubular portion surrounding the transferset and the tubular fluid transfer portion such that the major components of the transferset may be molded in one piece. In another embodiment, the transferset includes a cup-shaped cap which is received over the second tubular portion of the collar. In the preferred embodiments of the plastic collar of this invention which secures or is integral with a transferset attached to the container, the internal surface of the tubular portion which surrounds the rim of the container includes an annular resilient ring which is biased against the rim portion of the container to prevent rotation of the collar and transferset on the vial. In one preferred embodiment, the internal surface of this tubular portion includes an annular groove adjacent the free end of the tubular portion and the annular resilient ring is received and retained in the annular groove. The preferred embodiment of the plastic closure of this invention may also be formed of a relatively clear polymer or polymer alloy which maintains its clarity under the stress of deformation which is particularly advantageous where the plastic closure of this invention is utilized as a collar to secure and seal a transferset on the container.
The method of this invention then includes forming a plastic closure having a generally cylindrical tubular portion having an internal diameter generally equal to or slightly greater than an outside diameter of the rim portion of the container and an integral radial rim portion, disposing the closure over the rim of the container with the radial rim portion overlying the rim portion of the vial and the tubular portion surrounding the container rim, and then radially permanently deforming or crimping the free end of the tubular portion of the collar into the neck portion of the container, beneath the rim portion, permanently securing the closure on the container and sealing the container open end. In the most preferred embodiment of the method of this invention, the plastic closure of this invention is formed by injection molding the plastic closure from a polymeric alloy or composite having a relatively soft malleable polymer or co-polymer and a relatively rigid polymer, wherein a polymeric alloy or composite is formed during the injection molding. Where a resilient or polymeric ring is utilized to prevent rotation of the closure on the container, the ring may be co-injected with the polymer forming the closure or an annular groove may be formed in the tubular portion of the closure, adjacent the free end. The method then includes inserting the annular resilient ring in the groove prior to radial permanent deformation of the free end of the closure as described, such that the resilient ring is biased against the rim portion of the container. A thermoplastic elastomer may also be co-injected with the polymer forming the closure to form a coating or film on the inside surface of the closure which is integrally bonded to the polymer of the cap.
The plastic closure of this invention may be utilized with a vial or other medical container having a conventional elastomeric stopper or as a collar in combination with a transferset having a sealing member as disclosed in the prior art or more preferably the collar portion may be formed integral with components of the transferset. Where the plastic closure of this invention is used to seal a container having an elastomeric stopper, the proximate radial lip of the closure is received over and preferably biased against the resilient radial lip of the stopper during radial deformation or crimping of the free of the tubular portion of the closure beneath the rim of the container. The plastic closure of this invention thus eliminates the problems associated with malleable metal collars or caps, such as aluminum, and is relatively inexpensive, and simple to manufacture, particularly when compared with aluminum caps having a protective coating. The plastic closure of this invention assures an excellent seal of the container and can be injection molded in a clean environment or washed, if necessary. Finally, the plastic closure of this invention accommodates the tolerances of the vial and particularly the buildup of tolerance variations in the combination of a conventional vial and elastomeric stopper. Other advantages and meritorious features of the present invention will be more fully understood from the following description of the preferred embodiments, the appended claims and the drawings, a brief description of which follows.